Mercury isotope evidence for marine photic zone euxinia across the end-Permian mass extinction
Mercury isotope evidence for marine photic zone euxinia across the end-Permian mass extinction
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DOI：
10.1038/s43247-023-00821-6
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发表时间：
2023-05
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影响因子：
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通讯作者：
Ruoyu Sun;Yi Liu;J. Sonke;Feifei Zhang;Yaqiu Zhao;Yonggen Zhang;Jiubin Chen;Cong‐Qiang Liu
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文献类型：
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作者：
Ruoyu Sun;Yi Liu;J. Sonke;Feifei Zhang;Yaqiu Zhao;Yonggen Zhang;Jiubin Chen;Cong‐Qiang Liu
二叠纪末大规模灭绝（EPME）是显生宙最大的生物危机，其驱动力、杀灭和恢复机制仍在争论中。汞富集和汞同位素的沉积记录表明了火山活动对 EPME 的影响，但汞富集和同位素变化的原因仍存在争议。在这里，我们模拟了 EPME 中的汞同位素变化，以定量评估火山活动、陆地侵蚀和透光区 euxinia（PZE，有毒、富含硫化物的条件）的影响。我们的数值模型表明，虽然大规模火山活动仍然是汞广泛富集的主要驱动因素，但 EPME 中 Δ199Hg 同位素特征的负移不能像之前提出的那样用火山活动或陆地侵蚀来完全解释，而是需要在增强的 PZE 条件下通过海洋汞光还原进行额外的分馏。因此，我们的模型提供了进一步的证据，证明广泛且长期的 PZE 作为 EPME 和随后恢复受阻的关键杀伤机制。
The driving forces, kill and recovery mechanisms for the end-Permian mass extinction (EPME), the largest Phanerozoic biological crisis, are under debate. Sedimentary records of mercury enrichment and mercury isotopes have suggested the impact of volcanism on the EPME, yet the causes of mercury enrichment and isotope variations remain controversial. Here, we model mercury isotope variations across the EPME to quantitatively assess the effects of volcanism, terrestrial erosion and photic zone euxinia (PZE, toxic, sulfide-rich conditions). Our numerical model shows that while large-scale volcanism remains the main driver of widespread mercury enrichment, the negative shifts of Δ199Hg isotope signature across the EPME cannot be fully explained by volcanism or terrestrial erosion as proposed before, but require additional fractionation by marine mercury photoreduction under enhanced PZE conditions. Thus our model provides further evidence for widespread and prolonged PZE as a key kill mechanism for both the EPME and the impeded recovery afterward.